1. Technical Field
The present invention relates generally to cellular wireless communication networks; and more particularly to mobile station operation in a legacy mobile station domain communication network.
2. Related Art
Cellular wireless networks include a “network infrastructure” that facilitates wireless communications with mobile terminals operating within a particular service coverage area. The network infrastructure couples to other network elements to support numerous types of communications, for example, the Public Switched Telephone Network (PSTN), the Internet, et cetera. The network infrastructure may route communications to other subscribing wireless units, to terminals coupled to the PSTN, to terminals coupled to the Internet, or to terminals coupled via another network to one of these networks.
Various wireless interface specifications have been developed to standardize wireless communications between the mobile terminals and the network infrastructure and between components that comprise the network infrastructure. Wireless interface specifications include, for example, the Advanced Mobile Phone Service (AMPS) specifications, the Global System for Mobile communications (GSM) specifications, the Code Division Multiple Access (CDMA) specifications, and the Time Division Multiple Access (TDMA) specifications. Generations of these specifications are generally referred to as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), et cetera. Each advancing generation of standards typically performs and/or supports a greater number of services, a greater number of features, and provides better communication qualities. These operating specifications may also be partially deployed from generation to generation, for example, 2G to 2.5G.
Some partial generation wireless specification updates may be deployed using a legacy infrastructure. For example, a 2.5G network has been deployed using upgraded components of a 2G network. When moving from one generation to another generation, however, the network infrastructure must typically be rebuilt using new infrastructure components.
Network infrastructure replacement is both expensive and difficult to deploy. An additional problem resulting from the generational replacement relates to backward compatibility of subscriber services. With 3G networks, for example, a subscriber subscribes to 3G services, which includes a suite of services. A 3G subscription may include, for example, circuit switched voice services for the subscriber's 2G mobile terminal, packet switched voice service for the subscriber's 3G packet switched mobile terminal, packet data services for the subscriber's personal data assistant, and packet data services for the subscriber's notebook computer, among other services. Each of the subscriber's wireless devices, however, may not be compatible with the 3G infrastructures.
In a typical next generation 3G infrastructure, legacy terminal support will be provided. When 3G systems are deployed, 3G mobile terminals will be placed into service. In such cases, the 3G infrastructures will support the 3G services for the 3G mobile terminals as they operate within the respective service areas. The 3G mobile terminals, however, must also be serviced while roaming into legacy 2G wireless networks. Thus backward compatibility issues arise that have not heretofore been addressed.
Further, 3G wireless terminals may be placed in service within a legacy network, and thus will be limited in their operation to certain services. If such a 3G wireless device roams from its home service area (that is, the area for which the subscriber normally obtains service) into a visiting service area that supports all 3G packet switched services, the 3G wireless device should not be allowed to receive services to which it does not subscribe. In such case, the visited network must prevent delivery of these services.
Thus, there is a need in the art for a system and method that may be employed to support services for both legacy mobile terminals and next generation mobile terminals operating within a next generation wireless communication systems and further to support services for next generation terminals operating within next generation networks for which the subscriber has subscribed to legacy networks based services.